Researchers at Harvard create flow battery with ten-year life span

Scientists at Harvard University’s School of Engineering and Applied Sciences have developed a new battery which may be capable of holding its charge for “exceptionally long” periods of time.

It’s thanks to a type of rechargeable battery called a ‘flow battery’. In flow batteries, chemical compounds are dissolved in liquids which are separated by a membrane. This causes ‘ion exchange‘ through the membrane – the flow in flow battery – which generates electric current.

The Harvard research team – led by Professors Michael Aziz and Roy Gordon – was focused on the capability of organic molecules in liquid solutions. By using organic substances that had been engineered on a molecular level, the researchers were able to create a flow battery with a much improved storage capacity.

The key benefit here is the long life cycle of the battery. Where typical lithium ion batteries – the sort found in phones and laptops – are popular, they have a poor discharge/recharge cycle rate, typically not lasting for 1,000 full cycles. This means that they are not suitable for large-scale energy storage applications.

However, the flow battery tested by the Harvard researchers is incredibly efficient, losing just 1% of its total storage capacity per 1,000 cycles. Running at full efficiency, and losing no more than 1% of its capacity per cycle, means that the battery could last for as long as ten years before needing replaced.

Plus, because the battery uses organic molecules instead of inorganic ones, the battery fluid is non-toxic and non-corrosive. This means that the exterior materials, such as casing, tanks and pumps, do not need to be expensive. Cheaper materials can be used in the construction, bringing down the price of the unit and making energy storage cheaper than it currently is.

As renewable energy sources continue to grow in popularity and make up a greater share of the global energy mix, there are intermittency issues which must be resolved. This is referring to the naturally unreliable nature of solar and wind power, which can lead to National Grid instability if there is an energy deficit. Because of this, being able to store energy to cope with peak times of energy usage is one of the biggest hurdles facing the take-up of renewable energy sources.

The research team, with assistance from Harvard’s Office of Technology Development, are working alongside a number of companies to scale up the technology for industrial and commercial applications. If this tech can be used in large-scale sites, the reality of bringing substantial renewable energy reliance to the grid.